A Joke

Four surgeons are having a coffee break.1st surgeon says "Accountants are the best to operate on because when you open them up, everything inside is numbered."2nd surgeon says "Nah, librarians are best. Everything inside them is in alphabetical order."3rd surgeon says "Try electricians, man! Everything inside them is colour coded."4th surgeon says "I prefer Man U fans. They're gutless, spineless, heartless and their heads are interchangeable."